Subulicystidium tedersooi Ordynets, Scherf & Langer sp. nov. Figs 4g, h; 10f

Diagnosis.

Species with particularly narrow fusiform basidiospores, 8.5-11.5 × 2-2.5 µm and long, 85-125 µm, regularly encrusted cystidia.

Type.

VIETNAM. Ninh Bình Province: Cuc Phuong National Park, sampling area G2906, 20.3500, 105.6026, on fallen decayed twig, 15 Oct 2012, L.Tedersoo (TU 110894) .

Etymology.

tedersooi, named after Leho Tedersoo, an Estonian mycologist, the vigorous explorer of the global soil fungal diversity and collector of the type specimen.

Description.

Basidiomata annual, effused, resupinate, soft and fragile, arachnoid, thin, loosely adnate. Hymenophore smooth, finely velutinous due to numerous protruding cystidia, whitish. Margin thinning out, adnate.

system monomitic. All septa with clamps. Subicular and subhymenial layer weakly differentiated, consisting of richly branched hyphae 2-3 µm wide, thin-walled, with rough surface due to a subinvisible hyaline crystal sheath. Cystidia subulate, 85-125 × 4.5-5 µm, usually without basal swelling, terminal, with thick hyaline cell wall and an outer hyaline crystal sheath covering the whole cystidium except the acuminate apex. Crystal protrusions on cystidium are rectangular, moderately large, regularly arranged in longitudinal rows.

Basidia suburniform to cylindrical, 9-13 × 4.5-5, thin-walled, with 4 sterigmata and a basal clamp, occasionally with a thin hyaline crystal collar at the base. Basidiospores narrowly fusiform, L=(7.9-)8.4-11.5(-11.8) µm, W=(1.9-)2.1-2.6(-2.8) µm, Q=(3.4-)3.5-5.0(-5.7), N=81/2, with straight to slightly curved base, thin-walled, often with two large or many smaller oil drops, negative in Melzer’s reagent.

Additional specimens examined.

VIETNAM. Ninh Bình Province: Cuc Phuong National Park, sampling area G2906, 20.3500, 105.6026, on fallen decayed twig, 15 Oct 2012, L.Tedersoo (TU 110895) .

Remarks on species.

The narrow spores of S. tedersooi are comparable in width only with S. perlongisporum (see Fig. 10f vs. 10j). However, the spore length of two species drastically differs: 8.4-11.5 µm in S. tedersooi vs. 17-25 µm in S. perlongisporum (Boidin and Gilles 1988). S. tedersooi also has shorter basidiospores and longer cystidia than its sister species S. fusisporum (see Figs 4, 10 and 11 for spore and cystidia comparisons and Figs 12 - 14 for phylogenetic inference).